Nintendo game designer Shigeru Miyamoto, creator of Wii Fit, does a yoga pose as he demonstrates the game Thursday, April 17, 2008 in New York. "Our main premise in creating Wii Fit was (to) create a game that allows you to check your weight," said Miyamoto. (AP Photo/Tina Fineberg)

Nintendo is releasing what might be the first big-budget console game that can pull in that ever elusive segment: mothers.

Officially, Nintendo said Wii Fit, an exercise and health title, is designed for an "expanded audience." But the game, which goes on sale today, has the potential to attract what some marketers have called the chief household officer, a large but mostly unreached population of potential gamers.

The game's novel appeal is delivered through an electronic Wii balance board controller, sold in a bundle with Wii Fit for $90. The board, with multiple sensors, measures a player's weight and turns steps and shifts in balance into moves on screen.

Players can chart their weight and body mass index over time and work to improve them by engaging in about 40 activities including yoga, aerobic step routines, strength and training exercises, and balance games. The balance board can track the progress of up to eight players, so users can encourage each other toward their respective goals.

For an industry that's often been blamed for helping cause obesity and inactivity, Wii Fit is a chance to turn back the criticism by offering a game that targets health issues in a way that's fun.

"Most people don't enjoy working out, but we believe most people want to maintain a fit body and a healthy lifestyle," said Denise Kaigler, vice president of corporate affairs for Nintendo. "Wii Fit addresses that dilemma, allowing you to get fit in a fun and convenient way."

Wii Fit continues the breakneck momentum of the Nintendo Wii, which has sold more than 9 million consoles since it was released in November 2006. The Wii has created a huge shift in the gaming world, inviting millions of casual and nongamers, many of them women, to pick up the motion-sensing Wii remote controller and play games using gestures and waves.

The increase in new female gamers on the Wii has been noticeable, said Ricardo Torres, editor in chief of gaming Web site GameSpot, but Wii Fit can take it a step further. He said it could be what causes mothers to spring for the Wii themselves, not just for their kids.

"Moms have the purchasing power in the house, and this is a game that will catch her attention," Torres said. "Look at the way they're marketing it. They're not reaching out to hardcore gamers, who they know will want to get it, too, for the mini-skill games. They're showing off these other aspects like yoga and step aerobics that will hook a mom."

If Japanese sales are any indication, Wii Fit should do huge business in the United States. Since it was released in December, Nintendo has sold more than 2 million Wii Fit bundles in Japan, with almost 1 out of every 3 Wii owners buying the game and balance board.

The bigger question might be: Can you get your hands on one? Wii Fit already has sold out in pre-sales on Amazon.com and Walmart.com. EBay's pop culture expert Karen Bard told gaming Web site Punch Jump she expects the game to do bigger sales than Grand Theft Auto IV, which sold 2.85 million copies in the United States in its first five days, according to the NPD Group.

Billy Pidgeon, an analyst with IDC, said the expected popularity of the game likely will increase demand for the Nintendo Wii, which is still in short supply, although it sold more than 714,000 units last month in the United States.

Pidgeon said Wii Fit will provide more fuel to the casual gaming trend, which Nintendo has helped ignite with the Wii and its handheld counterpart, the Nintendo DS.

"With Wii Fit and games like Guitar Hero and Rock Band, they're becoming more of an on-ramp for gaming," Pidgeon said "People see more of the value in games and are getting into it."

While the balance board will come with Wii Fit, the game is not the only one that will use the innovative peripheral accessory. Nintendo said there are another 10 games on tap that will use the balance board, everything from skiing and snowboarding titles to a game from THQ called All Star Cheer Squad, which takes a player through a year in the life of a cheerleader.

"The balance board is exciting for the industry because it opens up a lot of different game play opportunities and interactive entertainment experiences," said Colin Sebastian, an analyst with Lazard Capital Markets.